Memory device with memory buffer for premature read protection

Abstract

Devices and methods for accurate reading of data in memory technology prone to drifting memory characteristics. An example device includes a memory array for storing data, and a memory buffer for storing a subset of the data in the memory array. A memory controller is configured to read data from the memory buffer if the data was written to the memory array before a predetermined duration of time, and to read the data from the memory array if the data is at least one of not valid or not available at the memory buffer.

Description

BACKGROUND[0001]The present invention relates to computer memory devices. More particularly, the present invention relates to management of memory devices with drifting electrical characteristics.[0002]Typical memory devices consist of memory cells fabricated with semiconductor materials. As memory device size continues to scale down and with the continuing drive to maintain low power consumption in memory devices, many issues arise from the limitations of the materials and their electrical properties. One such issue is the drifting of electrical characteristics utilized for reading memory states. An example of drifting read characteristics is the tendency of electric charge leakage in a capacitor memory cell.[0003]Another example is resistance drift in phase change memory (PCM) technology. Conventionally, PCM read operations measure resistance level to distinguish memory states. The resistance levels in PCM cells have a tendency to increase over time, after programming. The resista...

AI Technical Summary

Benefits of technology

The present invention is a memory device with a premature read protection scheme. This means that the memory device can prevent others from accessing data that has been written to the memory array before a certain time has passed. The memory device includes a memory array and a memory buffer, and a memory controller that can read data from the memory buffer if it was written to the memory array before a set amount of time has passed. This helps to ensure that data is only accessible to authorized individuals and reduces the risk of data being leaked or being tampered with.

Problems solved by technology

As memory device size continues to scale down and with the continuing drive to maintain low power consumption in memory devices, many issues arise from the limitations of the materials and their electrical properties.

One such issue is the drifting of electrical characteristics utilized for reading memory states.

The resistance drift makes reading the stored data from a PCM cell challenging because resistance contrast between two adjacent (in terms of resistance levels) memory states is gradually reduced over time, and resistance of different memory states may eventually overlap.

However, resistance drift is more problematic when a PCM cell is configured with a MLC scheme than a SLC scheme because the resistance margins between neighboring resistance levels are greatly reduced in MLC.

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